Walked this in August 2015, after these posts, having failed in 1978 when I was washed miserably off Cross Fell. It was certainly tougher in the '70's, but is most certainly still a challenge. I'll do it again as part of LEJOG in 2019, all being well, but I may look for detours round the boggy bits - e.g. the South Tyne Trail instead of Blenkinsopp Common.
Anyone found a better route to Scotland?